Exchange Server End of Support October 2025

Australia, Jul 9, 2025

Microsoft has announced that all existing versions of Exchange Server will be reaching end of support in October 2025. 

As of July 1st, Microsoft has released Exchange Server Subscription Edition (SE) as the successor to Exchange 2016/19 for customers that still require an on-premises server. 

Moving forward, SE will be the only supported version of Exchange and Microsoft will be taking steps to actively block unsupported Exchange versions, most notably by preventing acceptance of messages within Exchange Online. 

Many organisations have already completed migration to Microsoft 365 / Exchange Online, but in many cases, a legacy Exchange Server is still a critical part of their infrastructure. 

Are You Ready? 

As the end of support for Exchange Server 2016 and 2019 rapidly approaches, it's crucial for businesses to prepare for the transition. Whether you're an on-premises customer or a cloud customer who needs to retain an on-prem mail relay or management server, there are several key points to consider. 

Points to Consider for On-Premises and Cloud Customers 

For on-premises customers, the end of support means that Exchange Server will no longer receive updates, including security patches. This can leave your system vulnerable to threats and compliance issues. It's essential to plan for an upgrade or migration to ensure continued support and security. 

Microsoft 365 cloud customers who need to retain an on-prem mail relay or management server should also be aware of the implications. While your primary email services may be hosted in the cloud, any on-prem components will still be affected by the end of support. Ensure that these systems are updated or replaced to maintain security and functionality. 

Upgrade to Windows Server 2025 

It's important to note that this upgrade should also include Windows Server 2025, as the underlying operating system of existing servers is also approaching end of life. Upgrading both Exchange Server and Windows Server will ensure that your infrastructure remains secure and supported. 

I Have Migrated to Microsoft 365, Can I Decommission Exchange Server Entirely? 

If you've migrated to Microsoft 365, you might be wondering if you can decommission Exchange Server entirely. The answer depends on your specific needs. While Microsoft 365 provides comprehensive email services, some businesses may still require an on-prem Exchange Server for certain functionalities, such as mail relay or management tasks. Evaluate your requirements carefully before making a decision. 
 
SMTP Relay and Alternatives 

One critical aspect to consider is the SMTP relay. Many businesses use Exchange Server for SMTP relay, and the end of support means that this functionality may be at risk. It's worth exploring alternatives such as Azure Communication Services, which can provide robust and secure email relay capabilities. 

Licencing Considerations 

For many years, Microsoft has provided a free “Hybrid Server” licence to eligible Microsoft 365 Customers that require the server exclusively for management purposes. 

This licence is still available, however with the introduction of SE, customers will additionally need to maintain active Software Assurance or suitable cloud subscription licence. 

If the Exchange server is performing any roles other than management, such as hosting mailboxes, Edge Transport or SMTP relay, a full Exchange Server Licence (with active Software Assurance (SA)) will be required. 

Any locally hosted mailboxes must also be licenced, this includes service accounts, resources, etc. 

The mailbox licence requirement can be satisfied by either: 

  • Cloud subscription licenses for all users and devices that access Exchange Server SE (for example, Microsoft 365 E3 or E5 licenses); or 
  • Exchange Server SE Server licenses and CALs with Software Assurance (SA) 

     

Upgrade now with Logicalis 
Whether you are migrating to Microsoft 365 or upgrading your On-Premises Environment, Logicalis can take the hassle out of reviewing your current state, planning and executing on the migration ahead of the deadline. 

Is your organisation ready for Exchange Server SE? Contact our team to discuss your upgrade options here.

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